I'm going to stick to the Pennzoil Semi Syn that i was using in my previous boat once my Royal purple runs out. LOVE that royal purple stuff
but not going to pay $40 a gallon for it in a carb'ed 2 stroke. It still smokes with the full synthetic oil in it, nothing is going to stop that.
I have a feeling that the merc prem is best suited for an EFI/Direct injection motor which has much higher combustion temps than my carbed engine.
In 2 stroke lawn equipment, its either Stihl HP Ultra (synthetic) or Redline Racing oil. I fly R/C aircraft with 2 stroke engines on them, and after multiple flying seasons, the redline results in a piston that still looks new.